Yes, you should do a master reset for the best Windows 10 Mobile experience

Yesterday, Gabriel Aul stepped out from the coding confines of Microsoft to talk about Windows 10 Mobile and the next Insider build. Windows 10 Mobile build 10240 evidently has a severe enough bug to prevent its distribution to Insiders, leaving people on build 10166 instead. The good news is an even newer build is coming, likely in a few days so either later this week or early next.
This intro brings me to something I and many others have noticed when using these builds: do a hard reset (aka master reset) for a better Insider experience.

I realize that this is a rather cumbersome task, especially if you have lots of game saves and customizations. However, if you want the best experience it does seem doing a fresh install or hard resetting after an update is your best bet. Wiping away the old and letting the OS do its thing on fresh hardware is a superior experience.